<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <link rel="stylesheet" href="./index.css"><!--外部样式表-->
    <style>
        div{
            color:red;
        }
    </style>
</head>
<body>
    <div style='background-color:black'>
        小滴课堂
    </div>
</body>
</html>